The Sakhalin Region is the only region of Russia that is completely located on the islands.
It includes the island of Sakhalin with the adjacent small islands of Moneron and Tyuleniy, as well as the Kuril Islands.
It stretched from north to south for 948 km. Its maximum width is 160 km, and the minimum is only 26 km.
The Islands have a myriad of lakes, rivers, streams and waterfalls.
Sakhalin alone has more than 65.000 rivers and 17.000 lakes (both salt and fresh).
The island is separated from mainland Russia by the Tatar Strait and the Nevelskoy Strait, the Amur Estuary and the Sakhalin Bay, and from Japan by the La Perouse Strait.
From the west and south, Sakhalin Island is washed by the waters of the warm Sea of Japan, from the north and east by the cold Sea of Okhotsk.
Most of the territory is mountainous.
But the mountains are not very high: Mount Lopatina (1609 m) has risen above the sea level.